a) Field of the Invention
The invention relates to a compensating or adjusting support arrangement such as for a stacking table for a printing machine for printing envelopes, the top envelope of an envelope stack resting on a movable top surface being brought into a horizontal position and supplied by means of a suction device to the printing apparatus. The inventive arrangement may be in the form of a supplementary device for the printing machines. Such supplementary devices are suitable for printing machines for all standard printing procedures, i.e. letterpress, litho, screen and photogravure.
b) Background Art
In standard printing machines for envelopes, the envelopes are stacked in large numbers and conveyed via a suction feeder to the feed table on which the printing process is carried out. When stacking a large number of envelopes, a level difference occurs because of their flaps and/or multilayer gluing when unidirectionally positioned, the thicker areas of the envelopes are higher than the thinner areas and therefore it is not possible to ensure a horizontal position of the top envelope taken from the suction device. As a result, there is only a poor suction effect on the envelope and the printing process can no longer take place in a precise and accurate manner.
In order to prevent this, compensation is necessary and this has been done in the past by using, prior to the printing press, rollers, wedges or the like which are placed between the envelopes in the envelope stack and during the printing process, have to be regularly manually removed. Therefore, someone must always be present at the printing machine throughout the printing process.